ViewModels or ViewBag?

asp.net-mvc-4 viewmodel viewbag
Riddick picture Riddick · Dec 8, 2012 · Viewed 16k times · Source

I'm fairly new to MVC4, EF5 and ASP.Net, and I don't seem to be able to find a good answer anywhere.

Basically, Should everything be done through the viewmodel or is it Ok to also incorporate viewbag?

Say I have a method which populates a drop down list, and I am using a viewmodel to represent the output for the view.

Am I ok to use Viewbag.DropDown = PopulateDropdown(); or would it be better to incorporate this into the ViewModel, by creating a property to hold the List<SelectListItem> created by PopulateDropdown(); ?

I know how handy ViewBag is, but I'm yet to see any solid reason as to not use it? If anyone could also offer me some more insight, that would be fantastic.

Answer

Darin Dimitrov picture Darin Dimitrov · Dec 8, 2012

Basically, Should everything be done through the viewmodel or is it Ok to also incorporate viewbag?

Everything should be done inside a view model. That's what a view model is. A class that you specifically define to meet the requirements of your view. Don't mix ViewBags with ViewModels. It is no longer clear for the view where is the information coming from. Either use only a view model (approach that I recommend) or only use ViewBags. But don't mix the 2.

So in your particular example you would have a property on your view model which is of type IENumerable<SelectListItem> and inside your view you will use the strongly typed version of the Html.DropDownListFor helper to bind to the model:

@Html.DropDownListFor(x => x.ProductId, Model.Products)

Obviously those are only my 2 cents. Other people will say that mixing ViewModels and ViewBags is fine and I respect their opinion.

Related questions

ValidateInput(false) vs AllowHtml

I have a form that is used to create a memo, to do that I am using a rich text editor to provide some styling, this creates html tags in order to apply style. When I post that text, the …

Read More
asp mvc list product details in view using View Model

I am trying to list single product details in a view. The product specification changes dynamically because specifications are added row-wise in table, which means we can add huge number of specifications for each product (as done in ecommerce sites). …

Read More
How to pass json POST data to Web API method as an object?

ASP.NET MVC4 Web API application defines post method to save customer. Customer is passed in json format in POST request body. Customer parameter in post method contains null values for properties. How to fix this so that posted data …

Read More